The present invention relates generally to plasma cutting systems and other high power output welding-type systems such as welding and induction heating systems and, more particularly, to a one-piece consumable for use with such systems.
Plasma cutting is a process in which an electric arc is used to cut a workpiece. Plasma cutters typically include a power source, an air supply, and a torch. The torch, or plasma torch, is used to create and maintain the plasma arc that performs the cutting. A plasma cutting power source receives an input voltage from a transmission power line or generator and provides an output voltage to a pair of output terminals, one of which is connected to an electrode and the other of which is connected to the workpiece.
An air supply is used with most plasma cutters to help start the arc, provide the plasma gas to the torch, and cool the torch. A movable or fixed electrode or consumable serves as a cathode and a fixed or moveable nozzle serves an anode. The air supply creates a force to separate the electrode and tip, as the electrode moves away from the nozzle, an arc is created, and a plasma jet is forced out through the opening in the nozzle. The plasma jet causes the arc to transfer to the workpiece, and thus initiates the cutting process. In other plasma cutting systems, a high frequency starter is used to initiate the cutting process. In either arrangement, this electrode and tip are eventually worn down and must be replaced, hence, the term consumable.
During the cutting process, as the arc transfers from the electrode to the workpiece in the plasma, substantial heat is generated. The level of heat generated is partially determined by the type of material being worked, the power output required to work the material, and the type of consumable required to effectuate the desired work. Due to the high operating temperatures, the remaining working life of certain components, called consumables, is reduced during cutting. Cutting with an overheated or overused consumable can result in poor cut quality or reduced cutting speeds. As such, replacement of the consumable tip and electrode is dependent on operating conditions and may need to be done in the middle of a cutting job.
Due to the high temperatures generated during welding/cutting processes, an operator must take special precautions to protect oneself from the heat generated during the welding/cutting processes. This protection is often in the form of thick leather gloves and coats as well as protective hoods. Wearing leather gloves limits an operator's dexterity and makes manipulation and orientation of small components relatively difficult and time consuming.
Replacing the tip or the electrode requires removing the consumable assembly from the torch. The consumable assembly can include a shield, a shielding cup, a swirl ring, a tip, and an electrode. In order to change the consumable components of the plasma torch, an operator must handle and associate each of the relatively small components into the nozzle tip of the assembly. This task can be tedious and time consuming, and is exaggerated when replacement is needed in the middle of a cutting task. That is, due to the heat of the worn components attached to the torch, an operator must often attempt to change the consumable assembly while wearing protective gloves or wait for the assembly to cool. Orientating the consumable components relative to each other, and the torch, while wearing thick leather gloves, is often a time consuming, and occasionally frustrating, procedure.
It would therefore be desirable to design a one-piece consumable that can be easily manipulated by an operator.